Railway traffic controlling apparatus



April 10, 1934. R. A. MCCANN ET AL RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Sept. 23, 1931 Q31 we 88% NN .QQNN WEN 5w Sw ANN 3 ma T w ma m V n T mi N M W A .wv Q Q m w ll a B k QNNQN MNFNQN QWEE SQQN I T dwwww @Qw wag m5 @Rww 5S @NNN WES E n ww E @g N .K 7 S Q a Patented Apr. l0, 1934 RAILWAY TRAFFIC CONTROLLING APPARATUS Ronald A. McCann, Swissvale, and Henry S.

Young, Wilkinsburg,

Pa., assignors to The Union Switch & Signal Company, Swissvale, Pa, a corporation of Pennsylvania Application September 23, 1931, Serial No. 564,574 Renewed December 23, 1932 7 Claims.

Our invention relates to railway traffic controlling apparatus, and particularly to signaling apparatus for stretches of single track which are provided with passing sidings, and which ap- F paratus is controlled in part from a remote point such as a despatchers oihce. One feature of our invention is the provision of means for expediting and safeguarding the operation of the signals when two trains moving in opposite directions are to pass each other at a siding.

We will describe one form of apparatus embodying our invention, and will then point out the novel features thereof in claims.

.In the accompanying drawing, Fig. l is aview showing a layout of track and signals to which our invention may be applied. Fig. 2 is a diagrammatic view showing the circuit for a relay LZHD which controls signals L2 of Fig. 1. Fig. 3 is a diagrammatic view showing the circuits 720 for home relays LAZH and LBZH controlling signals A and B, respectively, of the signaling group L2. Fig. 4 is a diagrammatic view showing the circuit for the control of a relay lOHD, which relay in turn controls signal 10 in the layout shown in Fig. 1. Fig. 5 is a diagrammatic view showing the circuit for a relay 10I-IP which is associated with signal 10. Fig. 6 is a diagrammatic view showing the control of a stick relay 10S associated with signal 10 of Fig. 1. Fig. 7

530 is a diagrammatic view showing the circuit for a code repeater relay LZHS associated with signal group L2 of Fig. 1. Fig. 8 is a diagrammatic view showing the circuits for the control of time element relays lTP and lTPP, which enter into the control of the code repeater relay L2HS of Fig. 7.

Similar reference characters refer to similar parts in each of the several views. 7

Referring first to Fig. 1, the reference character D designates a stretch of single track, and the reference character E designates a passing siding which is connected with the track D by a switch 1. The stretch of track shown in the drawing is divided into track sections 10T, L2T and IT,

which sections are provided with the usual track circuits involving track relays 10TH, L2TR and lTR, respectively. Traffic moving toward the right through this stretch of track is governed by an automatic signal 10, which is one of the usual intermediate block signalsof an absolute permissive block signaling system, and traffic moving toward the left is governed by signal A or signal B of a group L2, according as switch 1 is in the normal or the reverse position. The sig- 5 nals of group L2 are controlled in part from a remote point, such as a despatchers office, and are also controlled in part by the track relays and by the apparatus associated with signal 10. The signaling system also involves an intermediate signal R2 governing traffic moving toward the right, and an automatic signal 11 governing traffic moving toward the left, but these two signals are only indirectly associated with apparatus embodying our invention.

Signal 10 is controlled by a repeater relay of current.

It will be seen that this circuit is open when a train occupies any part of the stretch between signals 10 and L2, and that it is also open when either relay L2HS or L2HD is energized. The control of the polarity of the current supplied to the relay lOHD does not into our present invention.

enter Referring to Fig. 5, the circuit for relay IOHP includes a front contact of relay 10HD, so that the repeater relay 10I-IP is energized when and only when home relay 10I-ID is energized.

Relay 10HP is a slow pick-up relay, and may, for example, require a period of three seconds after the relay becomes energized before its front contacts will close. A reason for the slow pick-up characteristic of this relay is explained in an application for Letters Patent of the United States, filed by R. A. McCann on April 22, 1931, Serial No. 532,026, for Railway trafiic controlling apparatus, but this reason is not necessary for an understanding of the present invention.

Referring now to Fig. 6, relay 108 is associated with signal 10 and is the usual directional stick relay for an absolute permissive block signaling system. This relay is provided with a pick-up circuit which includes a back contact of track relay 10TR, and a front contact of repeater relay 10HP. It is provided with a stick circuit including a back contact of track relay 10TH and a front contact 5 of relay 10S. Relay 108 is provided with a second stick circuit including its own front contact 5 and a back contact of relay IOI-IP, with the result that when relay 10S once becomes energized, it will remain energized as long as repeater relay 10HP is open.

Relay 10HP is so designed that its back contact will not open until the expiration of the time interval required for the relay to close.

Referring now to Fig. 2, relay LZHD controls the signals of group L2, as stated above. The circuit for this relay includes a pole changer operated by signal 11, a contact operated by signal 10 and closed only when the signal indicates stop, a back contact of stick relay 10S, and front contacts of track relays 10TR and L2TR. It follows that relay L2l-ID can be energized when and only when signal 10 is at stop, stick relay 108 is open, and track sections 10T and L2T are unoccupied.

Referring now to Fig. 7, the circuit for code repeater relay LZHS, which is also a directional relay for governing traffic moving toward the left, includes a normally open contact L, which is controlled from a remote point, such as a despatchers office, and which may be closed by manual operation of a suitable key or lever at the will of the despatcher. The circuit also includes a back contact of the code repeater relay RZHS associated with signal R2, and it furthermore includes a front contact of a relay I'ITP. It follows that relay L2I-IS cannot be energized unless relay lTPP is closed.

Referring to Fig. 8, relay lTP is a slow pick-up relay which is controlled by a front contact of track relay lTR, whereas, relay lTPP is a slow pick-up relay controlled by a front contact of relay l'IP. Each of these relays lTP and lTPP, may have a pick-up period of three seconds, with the result that after a train leaves section 1T a period of about six seconds will elapse before the relay lTPP will close.

Referring now to Fig. 3, the relay LA2H shown in this view, is the home relay for the control of signal A of the group L2, and relay LB2I-I is the home relay for the control of signal B of this group. The contact lKR is the usual indication contact operated by the switch 1, and this contact is swung to the left or to the right according as the switch is in the normal or the reverse position. Assuming that the switch is in the normal position, the circuit for relay LA2H passes from terminal X, through a contact R132 which is closed only when arm 13 of signal R2 is at stop, a contact RA2 which is closed only when arm A of signal R2 is at stop, a front contact of track relay lTR, a front contact of relay LZHS, a front contact of relay LZHD, contact lKR in the normal position, and the winding of relay LA2H to terminal Y. When switch 1 is reversed, so that contact lKR is swung to the right, relay LBZH instead of relay LA2H will be energized, assuming that the circuit is closed at all other points.

The operation of the apparatus is as follows: When a train moving toward the right passes signal 10, it will open the circuit for relay 10HD, and will also cause the stick relay 108 to become energized during the interval between the closing of the back contact of track relay 10TR and the release of the front contact of repeater relay 10I-IP. When the train enters section 1T, it will cause the usual OS indication to be given in the despatchers office. Assuming now that a train moving toward the left occupies the passing siding E, and is held by signal B of the group L2, the despatcher may, upon receiving the OS indication of the occupancy of track section 1T, operate the proper key to cause contact L of Fig. '7 to close, but relay L2HS will not be energized, because the front contact of relay l'I'PP will be open due to the occupancy of section l'I. The opening of track relay 10TR due to the entrance of the first train into section lOT will also open the circuit for relay LZHD. When this first train, which is moving toward the right, enters section L2T, it will open track relay L2TR, and this will keep the circuits open for both relays 10HD and L2HD. When the train moving toward the right passes out of section 1T, relay lTPP will close after the expiration of about six seconds, whereupon relay LZI-IS will become energized. In the meantime relay lOHP (Fig. 5), will have become energized, so that relay 103 will have become deenergized, and the result of this will be that relay L2I-lD (Fig. 2) will have become energized. The despatcher will also have taken suitable action to reverse switch 1, and by reference to Fig. 3, it will be obvious that relay LBZH will now be energized, so that signal B of the group L2 will be cleared to allow the train occupying siding E to enter the main track.

The reason for the provision of a six-second interval between the closing of track relay lTR and the closing of relay lTPP, is as follows: The circuit for relay 10HD includes a back contact of relay L2I-IS, and the circuit for relay L2HD includes a back contact of relay 10S. Consequently, if relay L2I-IS were allowed to close before relay 10HP becomes energized following the pick-up of track relay lTR, relay 10HD, and therefore relay lOI-IP, would remain deenergized, so that relay 10S would remain energized, and this would prevent relay LZHD from becoming energized to clear signal B of group L2. By providing the time interval represented by relay lTPP, we insure that after a train moving toward the right vacates section 1T, relay lOI-IP Will become energized before relay LZHS can become energized, and we thereby insure that relay 108 will release in order to permit relay L2HD to become energized. Although we have herein shown and described only one form of apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the "spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, a stretch of railway track divided into sections each of which is provided with a track relay, a first signal and a second signal governing traffic through said stretch, a slow pick-up relay controlling said first signal and itself controlled by 3. each track relay in said stretch, a normally open manually controlled relay for the control of said second signal, means for preventing said slow pick-up relay from being energized unless said manually controlled relay is open, means for pre- 11 venting said second signal from being cleared unless said slow pick-up relay is closed, and slow acting means operating after a train moving from the first signal toward the second leaves the last section in said stretch to prevent said manually controlled relay from becoming energized for an interval of time greater than that required for said slow pick-up relay to close.

2. In an absolute permissive block signaling system for railroads, a stretch of track provided 1 with track relays, a first signal forgoverning traffic in one direction through such stretch and a second opposing signal for governing trafiic in the opposite direction through said stretch, a

manually controlled relay, a directional stick rein opposite directions,

1,954,572 lay associated with the first signal, a circuit for the first signal controlled by the track relays of said stretch and including a back contact of said manually controlled relay, a circuit for the second signal controlled by the track relays of said stretch and including a front contact of said manually controlled relay and a back contact of said directional stick relay, means for energizing said directional stick relay when a train passes the first signal moving toward the second signal, and for maintaining said stick relay energized while the circuit for the first signal is open, and means for preventing the energization of said manually controlled relay for a predetermined time interval after said train passes out of said stretch to thereby permit the circuit for the first signal to close to release said directional stick relay.

3. In an absolute permissive block signaling system for railroads, an intermediate block signal having a line relay governed by trailic conditions in advance of said signal and a directional stick relay so controlled as to become energized when a train moves through the block in one direction and to remain energized thereafter as long as such train remains in the block, a manually controlled relay adapted when energized to establish the opposite direction of traflic in said block, and means for preventing the energization of said manually controlled relay when a train has entered said block and has caused the energization of said stick relay until the block has been unoccupied for a time interval sufiicient to permit said stick relay to again become deenergized.

4. In a railway signaling system, a stretch of track including two track circuits each having a track relay, a manually controlled relay controlled by a front contact of one of said track relays, a line relay controlled by front contacts of both of said track relays and by a back contact of said manually controlled relay, a repeater relay for said line relay, a directional stick relay having a pickup circuit including a back contact of the other of said track relays and a front contact of the repeater relay, and a stick circuit including a back contact of said repeater relay, and means for preventing the energization of said manually controlled relay for a predetermined time interval after said first track relay becomes energized.

5. In an absolute permissive block signaling system for railroads, the combination with a line relay for governing trafiic in one direction through a block, a repeater relay controlled by said line relay, and a directional stick relay controlled by said repeater relay, of a directional relay for governing opposing trafiic and having a back contact in the circuit for said line relay, and means operating when a train moving in said one direction leaves said block to prevent the energization of said directional relay for a predetermined time interval suflicient to permit the directional stick relay to become released.

6. In an absolute permissive block signaling system for railroads, a block section having a plurality of track circuits each having a track relay, a directional relay, a line relay controlled by all said track relays and by a back contact of the directional relay, a repeater relay controlled by the line relay, a directional stick relay controlled by the line relay and the track relay at one end of said block, a slow pickup relay controlled by a front contact of the track relay at the other end of said block and a circuit for said directional relay including a front contact of the slow pickup relay.

'7. In a remote control system, a detector section of track including a track switch, a track relay for said section, a pair of opposing signals including one for governing trafiic in each direction through said stretch, a directional relay, a circuit for one signal including a front contact of the directional relay, a circuit for the other signal including a back contact of the directional relay, a slow pickup relay controlled by a front contact of said track relay, and a manually controllable circuit for said directional relay including a front contact of said slow pickup relay.

RQNALD A. MCCANN. HENRY S. YOUNG. 

